Milk Fever old

Milk Fever or Hypocalcaemia is like an iceberg: we can only see 20% of the problem i.e. clinical milk fever cases. The vast majority of the effects of milk fever, in the form of sub-clinical milk fever, remain hidden to vets and farmers.

Milk Fever is caused by the rapid rise in the cow’s demand for calcium for colostrum/milk production, combined with the delayed ability of the cow to increase supply. The resulting drop in blood calcium levels causes milk fever.


Gateway Disease

Even from the earliest days it was known that cows with milk fever were more prone to other metabolic disorders, hence milk fever became known as a gateway disease.

Cows with Milk Fever:

  • 8% of cows with clinical milk fever die
  • 12% of cows with clinical milk fever are culled
  • Cows with clinical milk fever lose on average 500l of milk production
  • 3x times more likely to experience dystocia or hard calving
  • 3x times more likely to have a retained placenta
  • 8x times more likely to experience mastitis
  • Higher likelihood of displaced abomasum

Naturally, the associated health implications and loss in performance mean that avoiding milk fever, clinical or sub-clinical, in the first instance is a key priority today. The Cow Start Calcium bolus is a complimentary dietic mineral feed (Calcium Supplement) for the reduction of the risk of milk fever (hypocalcaemia) in dairy cows.

The Cow Start Calcium bolus is uniquely designed to enhance  two critical areas for the cow on the day of calving:
rapidly enhance the calcium status of the cow and also aid her immune response.

Each Cow Start Calcium bolus delivers 65g of Calcium (50% more than other boluses) and 4g of Magnesium, to aid calcium absorption. The bolus also supplies rumen protected vitamin E and Selenium as an aid in supporting her immune response.




Rapid Calcium delivery old

Unique Calcium Delivery:

  • More Calcium
  • The Cow Start Ca bolus delivers 65g of Calcium, 50% more than other Calcium boluses
  • Quick and Slow Release
  • Both Calcium sources in the Cow Start Ca bolus have been shown to rapidly increase blood calcium levels, within 30mins
  • The cow Start Ca bolus has a unique combination of 2 quick release Calcium Sources – Seaweed derived Calcium* and Calcium Chloride^ And also a sustained release Ca source – Seaweed derived Calcium*
  • Enhanced Calcium bioavailability
  • Magnesium plays a critical role in the cows hormonal response to low blood calcium status
  • The Cow Start Calcium bolus also contains 4g of a highly bioavailable Magnesium# source that works to enhance the bioavailability of the Calcium to the cow

How to Administer

How to administer Cow Start

For the reduction of the risk of milk fever
1 bolus at the first indication of, or at calving
A second bolus 12 – 15 hours later

For Supplementation following calcium injection
1 bolus 2 – 3 hours after calcium injection
A second bolus 12 – 15 hours later


  • Do not administer the bolus with excessive force.
  • Do not administer to a cow showing clear symptoms of clinical milk fever; such as a down cow, or a cow with an impaired swallowing reflex.
  • Damaged or broken boluses should never be administered to cows.

Product Description old

Cowstart Product Image

The Cow Start Calcium Bolus is a complimentary dietetic mineral feed (Calcium supplement) for the reduction of the risk of milk fever (Hypocalcaemia) in Dairy Cows.

  • The Cow Start Calcium Bolus provides both rapidly available and sustained release Calcium to the cow to help normalise blood calcium levels in the cow at her time of greatest calcium demand.
  • The Cow Start Bolus has a fat coating to ease swallowing and aid safe administration
  • Each 260g bolus delivers 65g of Ca and 4g of Mg to aid Calcium absorption.

Research old

On Farm Research

The results of recent on-farm research trials are highlighted below*

Cow Numbers
Control51Cow Start 52
Metabolic IssuesControlCow Start
Retained Placenta20
LDA (Left Displaced Abomasum)00

Health TestingControlCow StartP-Value
BHBA d140.650.46<0.0001
BHBA d210.690.46<0.0001
BHBA Overall 0.670.46<0.0001
Metricheck Score 0.730.79NS

Milk ProductionControlCow StartP-Value
Milk Volume (kg) 28.629.2NS
Fat (kg)1.491.54NS
Protein (kg).991.02NS
Fat and Protein (kg)2.492.55NS

Trial carried out in Spring 2018
3 Irish spring calving herds
Average herd size 340 cows

*Full research whitepaper is available upon request

Calcium Source Research

The calcium in the Cow Start Calcium bolus comes from 2 proven calcium sources; Calcium Chloride as a rapid release calcium source and seaweed derived calcium which provides rapidly available calcium and a more sustained release at the intestine to give the cow the ideal profile of calcium release over 12 hours. The Cow Start Calcium bolus uniquely offers two rapidly available calcium sources.

Calcium Research Charts



Co. Cork


Tel: +353 (0) 87 148 6379